I have some chemical products which need to be tested for their anti-tumoral property. For this I dissolved them in 100% DMSO and later diluted them in Medium cell culture (0,1 nM to 100µM). I use the same concentration of DMSO (0,1nM to 200µM) , as control. after 72H I do my MTT essay and I calculate cell survival (%) = treated cell/ Treated cell by the same concentration of DMSO)*100.
The problem that my results are the same of DMSO.
Can I get some Idea to improve my results. Can I get another experimental ideas.
Your suggestions will be highly appreciated.
First of all what is your DMSO-induced growth inhibitory effects in each cell lines considered individually as compared to the same cell lines that never "saw" or "smell" DMSO?
Best regards
Robert
It thus seems at first glance that the concentration of DMSO you are using is too high and masks potential growth inhibitory effects of your compound of interest.
Two questions:
1) what is the highest concentration vol / vol (in %) of the DMSO you use in your culture and in the control?
2) how have you ordinated your multi-wells between control and treated conditions?µ
Best regards
Robert
The highest concentration of DMSO is 60µl in 3ml of medium and after I do a serial delution.
I use 2 multi wells plats: one for my drug and another for DMSO and I use the same dilution for my moleculs and DMSO from 0 to 200µM.
My serial delution are:
(1) 60µL of DMSO or drug + 3ml of medium
1ml of (1)+ 1ml of medium (2)
200µL from (2) + 1,8ml intel 7 conditions.
Best regards
OK. But what is the % decrease in cell line growth with the highest DMSO concentration as compared to the same cell line without DMSO?
Best regards
Robert
So, the last question is what is the highest DMSO concentration you used "on" your cell lines when testing your compound.
I already think that the absence of "significant" data comes from the DMSO-induced toxicity.
Best regards
Robert
So, Zahira, if I understand well all these points, I think that you see no significant data because the DMSO-induced toxicity is too high and masks the potential growth inhibitory effects of your extracts / compounds.
Usually, you cannot go above 0.1% (vol/vol) as a final "concentration" of DMSO to test potential growth inhibitory effects.
I however hope that other RG members will comment my response because the possibility actually remains that I am wrong.
Best regards
Robert
Hi Zahira, I agree with Mark's comment above. My rule of thumb is to try to use 1 ul of DMSO per 1ml. So, when making my drug stock I make sure the concentration is high enough that I'll be using around 1ul per mL. My control for my assay is then 1ul per mL or 0.1%. The amount of DMSO you are using is very high and is enough to kill the cells by itself. I tested the IC50 of DMSO in my cell lines and it was between 1.5-3.5% in about 8 cell lines I tested (ewing sarcoma and rhabdomyosarcoma cell lines).
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